.chapter-four-archive-page {
  --paper: #f4f3f5;
  --accent: var(--rainbow-purple);
  overflow: hidden;
  background: var(--paper);
}

.chapter-four-archive-page .chapter-header,
.chapter-four-archive-page .chapter-index-footer {
  border: 0;
  background: rgba(244, 243, 245, .92);
}

.chapter-four-archive-page .index-introduction {
  width: min(335px, 25vw);
}

.chapter-four-archive-page .index-introduction h1 {
  max-width: 330px;
  font-size: clamp(28px, 3.35vw, 56px);
}

.chapter-four-archive-page .index-introduction__subtitle,
.chapter-four-archive-page .index-introduction__zh {
  max-width: 285px;
}

.c4-stack-field {
  position: fixed;
  inset: 57px 0 31px;
  overflow: hidden;
  perspective: 1800px;
  perspective-origin: 53% 48%;
  background:
    radial-gradient(circle at 50% 44%, rgba(255,255,255,.92), rgba(244,243,245,.52) 48%, rgba(244,243,245,.96) 78%),
    linear-gradient(115deg, rgba(240,62,83,.045), rgba(255,241,0,.035) 35%, rgba(0,251,255,.035) 67%, rgba(153,51,112,.045));
  isolation: isolate;
}

.c4-stack-field::after {
  content: "";
  position: absolute;
  inset: 0;
  z-index: 1;
  pointer-events: none;
  background: radial-gradient(ellipse at 54% 75%, rgba(23,23,22,.08), transparent 31%);
}

.c4-stack-field__background {
  position: absolute;
  top: 52%;
  left: 52%;
  z-index: 0;
  margin: 0;
  color: transparent;
  font-family: var(--font-display);
  font-size: clamp(78px, 12.5vw, 200px);
  font-weight: 600;
  line-height: .69;
  letter-spacing: -.075em;
  text-align: center;
  -webkit-text-stroke: 1px rgba(54, 87, 184, .09);
  transform: translate(-50%, -50%);
  user-select: none;
}

.c4-layer-stack {
  --stack-spin: -10deg;
  --stack-tilt-x: 0deg;
  --stack-tilt-y: 0deg;
  position: absolute;
  top: 50%;
  left: 54%;
  z-index: 10;
  width: min(47vw, 760px);
  aspect-ratio: 2646 / 1871;
  cursor: ns-resize;
  transform:
    translate3d(-50%, -43%, 0)
    rotateX(calc(58deg + var(--stack-tilt-x)))
    rotateZ(var(--stack-spin))
    rotateY(var(--stack-tilt-y));
  transform-style: preserve-3d;
  transform-origin: center center;
  transition: transform 900ms cubic-bezier(.16, 1, .3, 1);
  will-change: transform;
}

.c4-layer-stack.is-focused {
  cursor: default;
  transform: translate3d(-50%, -50%, 0) rotateX(0deg) rotateY(0deg) rotateZ(0deg) scale(1.22);
}

.c4-layer-list {
  position: absolute;
  inset: 0;
  margin: 0;
  padding: 0;
  list-style: none;
  transform-style: preserve-3d;
}

.c4-archive-layer {
  position: absolute;
  inset: 0;
  z-index: var(--layer-order);
  overflow: hidden;
  background: var(--layer-color);
  box-shadow: 0 20px 34px rgba(23,23,22,.16), 0 4px 8px rgba(23,23,22,.1);
  opacity: var(--layer-opacity);
  pointer-events: none;
  transform:
    translate3d(var(--layer-x), var(--layer-y), var(--layer-z))
    scale(var(--layer-scale))
    rotateZ(var(--layer-rotation))
    rotateX(var(--page-rx, 0deg))
    rotateY(var(--page-ry, 0deg));
  transform-style: preserve-3d;
  transform-origin: center center;
  transition:
    transform 920ms cubic-bezier(.16, 1, .3, 1),
    opacity 620ms ease,
    filter 620ms ease,
    box-shadow 620ms ease;
  will-change: transform, opacity;
  backface-visibility: hidden;
}

.c4-archive-layer.is-nearby { pointer-events: auto; }

.c4-layer-hit {
  display: block;
  width: 100%;
  height: 100%;
  padding: 0;
  overflow: hidden;
  border: 0;
  outline: 0;
  background: transparent;
  cursor: grab;
  touch-action: none;
}

.c4-archive-layer.is-dragging {
  z-index: 80;
  transition: none;
}
.c4-archive-layer.is-dragging .c4-layer-hit { cursor: grabbing; }

.c4-layer-stack.is-focused .c4-archive-layer:not(.is-active) {
  opacity: 0 !important;
  pointer-events: none;
  filter: blur(7px);
  transform:
    translate3d(var(--layer-x), calc(var(--layer-y) + 82px), var(--layer-z))
    scale(.9)
    rotateZ(var(--layer-rotation));
}

.c4-layer-stack.is-focused .c4-archive-layer.is-active {
  z-index: 90;
  pointer-events: auto;
  transform:
    translate3d(0, 0, 120px)
    scale(1.015)
    rotateX(var(--page-rx, 0deg))
    rotateY(var(--page-ry, 0deg));
}

.c4-layer-stack.is-focused .c4-layer-hit { cursor: grab; }
.c4-layer-stack.is-focused .c4-stack-axis { opacity: 0; }

.c4-layer-hit:focus-visible {
  outline: 2px solid var(--rainbow-cyan);
  outline-offset: -4px;
}

.c4-archive-layer::after {
  content: "";
  position: absolute;
  inset: 0;
  pointer-events: none;
  opacity: .17;
  background: linear-gradient(102deg, rgba(255,255,255,.38), transparent 20%, transparent 76%, rgba(255,255,255,.18));
  mix-blend-mode: soft-light;
}

.c4-archive-layer img {
  display: block;
  width: 100%;
  height: 100%;
  border: 0;
  object-fit: fill;
  user-select: none;
  -webkit-user-drag: none;
}

.c4-archive-layer.is-active {
  box-shadow: 0 34px 58px rgba(23,23,22,.28), 0 8px 14px rgba(23,23,22,.18);
  filter: saturate(1.04) contrast(1.015);
}

.c4-stack-axis {
  position: absolute;
  top: 50%;
  left: 50%;
  width: 8px;
  height: 8px;
  border: 1px solid rgba(23,23,22,.44);
  border-radius: 50%;
  background: var(--rainbow-yellow);
  box-shadow: 0 0 0 6px rgba(255,241,0,.12);
  opacity: .7;
  transform: translate3d(-50%, -50%, 42px);
  transition: opacity 260ms ease;
}

.c4-stack-instruction {
  position: absolute;
  bottom: 42px;
  left: 54%;
  z-index: 14;
  display: grid;
  width: min(590px, 46vw);
  grid-template-columns: 1fr auto 1fr;
  gap: 20px;
  margin: 0;
  color: rgba(23,23,22,.46);
  font-size: 7px;
  letter-spacing: .08em;
  text-transform: uppercase;
  transform: translateX(-50%);
}
.c4-stack-instruction strong { color: var(--ink); font-weight: 400; text-align: center; }
.c4-stack-instruction span:last-child { text-align: right; }

.c4-axis-label {
  position: absolute;
  z-index: 4;
  color: rgba(23,23,22,.38);
  font-family: var(--font-display);
  font-size: clamp(12px, 1.4vw, 23px);
  letter-spacing: .035em;
  text-transform: uppercase;
}
.c4-axis-label--top { top: 16%; left: 55%; transform: translateX(-50%); }
.c4-axis-label--right { top: 48%; right: 6%; transform: rotate(90deg); }
.c4-axis-label--bottom { bottom: 11%; left: 54%; transform: translateX(-50%); }
.c4-axis-label--left { top: 48%; left: 26%; transform: rotate(-90deg); }

.c4-stack-readout {
  position: fixed;
  right: 22px;
  bottom: 58px;
  z-index: 22;
  width: min(300px, 23vw);
  padding: 12px 13px 11px;
  border: 0;
  border-radius: 12px;
  background: rgba(244, 243, 245, .2);
  -webkit-backdrop-filter: blur(10px) saturate(1.08);
  backdrop-filter: blur(10px) saturate(1.08);
  box-shadow:
    inset 0 0 0 1px rgba(255, 255, 255, .34),
    inset 0 1px 0 rgba(255, 255, 255, .52),
    0 6px 18px rgba(23, 23, 22, .045);
  font-size: 8px;
  letter-spacing: .04em;
}
.c4-stack-readout > span { color: var(--rainbow-purple); }
.c4-stack-readout h2 {
  margin: 8px 0 7px;
  font-family: var(--font-display);
  font-size: clamp(20px, 2vw, 32px);
  font-weight: 400;
  line-height: .9;
  letter-spacing: -.035em;
}
.c4-stack-readout > p { margin: 0; font-family: var(--font-zh); font-size: 10px; line-height: 1.45; }
.c4-stack-readout dl { margin: 15px 0 0; }
.c4-stack-readout dl div { display: grid; grid-template-columns: 82px 1fr; padding: 5px 0; border: 0; }
.c4-stack-readout dt { color: rgba(23,23,22,.48); }
.c4-stack-readout dd { margin: 0; }
.c4-stack-readout a { display: block; margin-top: 10px; padding-top: 0; border: 0; }
.c4-stack-readout a:hover { color: var(--rainbow-purple); }

@media (max-width: 900px) {
  .chapter-four-archive-page { overflow-y: auto; }
  .c4-stack-archive { min-height: 960px; }
  .c4-stack-field { position: absolute; inset: 57px 0 31px; min-height: 872px; }
  .chapter-four-archive-page .index-introduction { width: calc(100vw - 44px); }
  .chapter-four-archive-page .index-introduction h1 { max-width: 76vw; }
  .c4-layer-stack { top: 46%; left: 50%; width: min(82vw, 690px); }
  .c4-axis-label--left { left: 4%; }
  .c4-axis-label--right { right: 1%; }
  .c4-stack-readout { right: 22px; bottom: 48px; left: 22px; width: auto; }
  .c4-stack-readout h2 { font-size: 20px; }
  .c4-stack-readout > p,
  .c4-stack-readout dl,
  .c4-stack-readout a { display: none; }
  .c4-stack-instruction { bottom: 205px; left: 50%; width: calc(100vw - 44px); }
}

@media (prefers-reduced-motion: reduce) {
  .c4-archive-layer { transition-duration: 1ms; }
}

@media (prefers-reduced-transparency: reduce) {
  .c4-stack-readout {
    background: rgba(244, 243, 245, .94);
    -webkit-backdrop-filter: none;
    backdrop-filter: none;
  }
}